Method of welding



Oct. 27, 1925. 1,559,415

T s. FULLER METHOD. OF WELDING Filed May 20. 1922 ,f'g-v 2 I 1111 61170?! /4 I SFaller, I

m3 Azzomey Patented Oct. 27, 1925.

UNITED STATES PATENT. OFFICE;

TRUMAN s. EULLEE, or SCHENECTADY, NEw YORK, nssrenon T0 GENERAL ELEc- Tmo COMPANY, A conrona'rron on NEW YORK METHOD OF WELDING.

. Application filed May 20, 1922. Serial No. 562,308.

To all whom it may canoe-m Be it known that I, TRUMAN S. FULLER, a citizen of the UnitedStateaTesiding at Schenectady, in the county of Schenectady, State of New York, have invented certain new and useful Improvements in Methods of Welding, ofwh'ich the following is a speci fication.

1 My invention relates to a method of welding and has for its object the provision of asimple, reliable and ellicient method whereby two dissimilar metals maybe welded.

In one of its aspects my invention has application to protective devices used in electric furnaces, for example, such as described and claimed in a copending application of Tycho Van Aller, Serial No. 556,782, filed April 26, 1922, assigned to the same assignee as this invention. In such devices a fusible element is supported in the interior of the furnace by two insulated leads made of electrically conducting, heat refractory material which extend through the wall of the furnace. My invention has for one of its objects the provision of a method whereby a good electrical. connection can be made between the fusible element and the leads in these devices. Obviously, however, my invention has a general application in the welding of dissimilar metals.

In effecting a weld in accordance with my invention, I first make a mechanical oint or connection between the parts to be welded, then apply a flux to the joint, and

finally heat the joint until the metal having the lower melting point; fuses and unites with the other.

T For a better understanding of my inven .tion reference should be'had to the accom panying drawing in which Fig. 1 illustrates a method of welding metals in accordance withmy inventiom'while Fig. 2 shows a furnace fuse in the'construction of which my. invention is particularly applicable.

Referring to the" drawing, the fuse 10 comprisestwo electrically conducting leads 11 and 12 made of a suitable heat refractory material, such as nickel chromium resistance alloy, which are held in arallel relation and insulated from each ot er in a suitable insulator 13. The insulator 13 extends through the wall 14 of the furnace and may --be conveniently mounted in the wall in a sheath '15. Connecting the inner ends .of the leads 11 and 12 isa short link16 madeof a ingpoint of the element 16.

suitable non-oxidizable material fusible at of forming a simple and reliable electricalconnection 17 between the fusible element 16 and the leads 11 and 12; This joint is preferably welded so as to provide for a permanent electrical connection which is not affected by the temperatures to which it is exposed. Obviously the usual methods of making welded joints are impracticable for the reason that it would be extremely difficult if not practically impossible to carry them out due to the fact that the melting points of the materials forming the leads and the fusible element are dissimilar.

Inmaking this welded joint in accordance with my invention, I provide a recess 18 in the end of one of the conducting leads 11. The goldor silver fusible element 16 is then inserted in the recess18 and the walls of the recess reduced or contracted, ,such as by swaging, tightly onto the element 16 so as to secure it in place. good mechanical joint. A small amount of flux 19, such as borax, is next applied to the joint at the line of contact between the element 16 and the lead 11, the lead being held in a vertical position as shown in the draw- ,ing. Heat is then applied to the joint, for example, by means ofa gas torch 20, and the temperature of the joint raised to the melt- Obviously, care must be taken not to overheat the fusible element as its melting point is ap proached; otherwise, the element will flow or melt down. .The precise period at which This results in a r may be conveniently ascertained by applying a pressure tending'to force ,the element 16 further into aperture 18. This pressure may be appliedthrough the agency .of a pair of pliers 21. "Under these conditions.

when the melting point of the portion of the element 16 at the joint 17 is reached, a very slight yielding or collapse of the eleeral ment will be felt, This signifies that the portion of the element inserted in aperture 18 has melted sufiiciently to unite with the material forming the lead 11, whereby a Welded joint having good electrical conductivity is formed. Immediately thereafter the source of heat 20.is removed and the parts allowed to cool. It will be understood that the lead 12 will be connected to the opposite end of element 16 in a similar manner. The 'oints are now boiled in water for sevours for the purpose of removing all traces of the borax used as a flux. This treatment is necessary due to the fact that the borax has a tendency, when exposed to high temperaturesin the furnace, to attack the nickel chromium allo forming the conducting leads. In the nal operation the leads and the element are bent in the hairpin form shown in Fig. 2 and inserted in the insulator 13.

Itwill be observed that in carrying out my method of making a welded joint, a good mechanical connection is first made. This brings the parts to be welded into intimate contact and maintains them in intimate contact durin the completion of the weld. Oxidation is thus prevented, the parts are held in a definite relation, and the making of the weld is otherwise facilitated so that its successful completion is assured. By means of my invention the welding operation, formerly very difficult to perform and often resulting in failure, is made possible of performance by the ordina skilled worker. By the use of my invention waste of material may be avoided which is very desirable on account of the precious metals, such as gold or silver, used for the fusible element.

While I have described my invention as embodied in concrete form and as operating in a specific manner. in accordance with the provisions of the patent statutes, it should be understood that I do not'limit my invention thereto, since various modifications thereof will suggest themselves to those skilled in the art without departing from the spirit of my invention, the scope of I which is set forth in the annexed claims.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. The method of joining two metallic rods having dissimilar melting points which consists in forming a recess in the one having the higher melting point, inserting the other in said recess, securing the two by compressing the Walls of said recess, applying a flux to the joint thus formed, and then heating the joint until the rod having .the lower melting point fuses at the joint and unites with the other while holding said rods in such position that said recess forms a receptacle for the portion of the rod'inserted therein.

The method of welding a non-oxidizable fuse wire to a heat refractory conductor, which consists in forming a recess in the conductor, inserting the wire in said recess, compressing the walls of said recess to secure the wire therein, applying a flux to the joint thus formed, heating the joint until the wire fuses at the joint and unites with the rod while holding said rodwith the recess uppermost and then dissolving ofi the excess flux.

3. The method of welding two metallic members having dissimilar melting points which consists in forming a mechanical joint between said members such that the member having the higher melting point forms an enclosing receptacle for a portion of the other member, and then heating the joint until said portion fuses and unites with the surrounding metal of the receptacle.

4. The method of Welding two metallic rods having dissimilar melting points, the rodhaving the higher melting point being of greater diameter, which consists in f'orming a longitudinally extending recess in one end of the rod having the higher melting point, inserting. a portion of the. rod of lower melting point in said recess, compressing the sides of said recess on said portion-to form a mechanical joint, holding said rod of higher melting point in a substantially vertical position with the joint uppermost whereby said recess forms an enclosing receptacle for said portion, and then heating said joint until the inetal of lower melting point fuses in said receptacle and unites with the walls thereof.

In witness whereof, I have hereunto "set my hand this 19th day of May, 1922.

v TRUMAN FULLER. 

